It is common to connect separate adjacent pieces of carpet to each other along a seam formed across the butted edges of the pieces, with a strip of tape being extended along the edges and being lapped over and bonded to the edges. For large carpet pieces that are difficult to move about, such as with wall-to-wall carpeting, where each piece of carpet may be 12 or 15 feet wide, it is desirable to secure the tape to the carpet pieces while the pieces are each laid in place on the supporting floor surface. This means that the carpet backing is against the supporting floor surface or cushioning pad, and the heat-activated seam tape is under the carpet pieces and against the carpet backing as the pieces are being butted together to orient the seam. This means also that the seam tape is completely hidden on the underside of the carpet after the seam has been established; and that all efforts to secure the seam must be taken from the upper side of the carpet, and then only through the carpet itself.
In establishing the seam, a heat-sensitive adhesive or hot-melt substance, on the face of the tape, is positioned against the carpet backing and is heated to become tacky. The carpet pieces are then pressed against the tacky surface of the tape to provide good proximate contact and probable bonding at the seam. U.S. Pat. Nos. 3,660,191 and 4,438,323 illustrate heaters of the type that can be used to heat the tape sufficiently to activate the adhesive; and U.S. Pat. No. 4,439,904 illustrates a roller tool of the type that can be rolled back and forth over the seam to establish good proximate contact between the tape and carpet backing.
One problem in establishing a seam as noted, however, is that the adhesive does not set immediately to secure the seam, but must be cooled down considerably. For example, the temperature to which the tape is heated to activate the adhesive may be between 250 degrees and 300 degrees Fahrenheit. Although some holding power is provided with the tape at this temperature, the carpet pieces and tape really need to be held together under some pressure until the adhesive has coooled to perhaps below 150 degrees to 200 degrees Fahrenheit. In practice, this may be accomplished by moving a roller tool repeatedly back and forth over the seam until the adhesive sets sufficiently. This can make the pace of setting up the seam quite slow and laborious.
In an effort to speed up the pace and ease the work effort, many professional carpet layers have tried placing a weight on the formed seam, so as to hold the carpet pieces in place until the adhesive cools sufficiently and sets. The weight then may be progressively moved or "inched" along the seam, at the same or related pace as the seam ahead is being initially established. A tool box or tray from a tool box is frequently used as such a weight, as it may seem to provide enough size and cover a fairly extensive length along the seam and enough weight to hold the carpet pieces in place across the seam.
However, the use of such a weight frequently has created unwanted and highly detrimental results. As examples, the exposed face of the carpet under the weight frequently can become "matted", "puckered-up", or discolored, or the seam itself can not hold to cause seam separation. Each or all of these problems by itself not only may be severe; but the same frequently may not even be dectected until long after the weight has been removed and the carpet has cooled down to room temperature. This embarassingly may be too late, and/or quite costly to correct, as many additional linear feet of carpet seams may also have been finished by the time the detrimental results are discovered. Moreover, the weight may trap heat in the underlying carpet seam, to provide that its use questionably might not even increase the pace of establishing the seam and often might cause seam separation because the seam is not set.